1. Field of the Invention
This invention relates to refrigeration purging systems used for the removal of air and other non-condensible gases from a refrigeration system and particularly the purging apparatus used in refrigeration systems employing two or more condensers.
2. Description of the Prior Art
In air conditioning large buildings, and in other applications, it is often necessary to provide both cooling and heating simultaneously. For example, the outer portion of the building will require heating in cold weather to compensate for heat loss through walls and windows; while the inner portion or core of the building will require cooling to compensate for the heat buildup in the center or unexposed portions of the building. During warm weather the heating requirement will diminish and the entire building may require cooling. In order to provide both heating and cooling, refrigeration systems have been developed which utilize a conventional compressor, condenser, evaporator system to promote cooling and which employ a second or high pressure condenser to provide heating. The heating condenser receives hot refrigerant vapor from the second, or higher, stage of a multiple stage compressor. The hot vapor is condensed in the heating condenser, heating water or other suitable medium to a temperature sufficient for use in heating the building.
In refrigeration systems the accumulation of non-condensible gases and other contaminants within the system reduce the efficiency of the system and must be periodically removed. To this end purge systems are utilized which normally use a chamber which accumulates non-condensibles by taking samples of the refrigerant from the top of the condenser, condensing the refrigerant and leaving the non-condensible to collect in the chamber. The chamber is cleared to atmosphere when the pressure in the chamber is nearly the same as the pressure in the condenser. However, with the utilization of two condensers at different pressures, which may or may not be operating at a given time, it is necessary to select one condenser, usually the one with the highest pressure for both sampling of the refrigerant and clearing of the chamber.